336 UPPER LIP OF MANATEE may get still more numerous This large number of grinding teeth is obviously suggestive o1 the Whales, with which th« Sirenia are believed by some tc be allied. It is at least a re- markable coincidence that thes* two aquatic groups of mammal* should both have assumed the same indefinite tooth formula It is correct to say assumed,, sinc€ extinct forms of Manatees, sue! as HalitJierium and Prorastoma have not a continuous successior of molars. The brain of the Manatee is, contrary to the usual arrangement among aqua- tic mammals, smooth, and onlj marked by one or two fissures. The Manatee * is black iu colour, its thick skin being wrinkled. The animal is assisted in feeding by a curious mechan- ism of the upper lip ; this is split in two, and the two halves, which are furnished with strong bristles, can play upon each other like the points of a pair of forceps. The flippers are furnished with nails, save in M. inunguis, but in the nailed forms it is not every finger which is thus armed. Hdlieore^ the Dugong, is an entirely Oriental and Australian 1 Beddard, " Notes upon thts Anatomy of a Manatee (Maaiatus inunguis},"Proc. Zool. S&c* 1897, p. 47, 2 See Kiikentha-l in Semon's ** Zoolog, Forschuiigen," Dentesvhr. Jen. J^angkavel, «' Eter Dugong," Zwl. 1896, p. 337.